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When problem size matters: differential effects of brain stimulation on arithmetic problem solving and neural oscillations.

Rütsche B, Hauser TU, Jäncke L, Grabner RH - PLoS ONE (2015)

Bottom Line: After the stimulation, we recorded their neural activity using EEG while the participants solved small and large arithmetic problems.Likewise, the lower-alpha desynchronization in large problems increased, whereas the theta synchronization in small problems decreased.These findings reveal that the LPPC is differentially involved in solving small and large arithmetic problems and demonstrate that the effects of brain stimulation strikingly differ depending on the involved neuro-cognitive processes.

View Article: PubMed Central - PubMed

Affiliation: Research on Learning and Instruction, Institute for Behavioral Sciences, ETH Zurich, Zurich, Switzerland; Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Zurich, Switzerland.

ABSTRACT
The problem size effect is a well-established finding in arithmetic problem solving and is characterized by worse performance in problems with larger compared to smaller operand size. Solving small and large arithmetic problems has also been shown to involve different cognitive processes and distinct electroencephalography (EEG) oscillations over the left posterior parietal cortex (LPPC). In this study, we aimed to provide further evidence for these dissociations by using transcranial direct current stimulation (tDCS). Participants underwent anodal (30min, 1.5 mA, LPPC) and sham tDCS. After the stimulation, we recorded their neural activity using EEG while the participants solved small and large arithmetic problems. We found that the tDCS effects on performance and oscillatory activity critically depended on the problem size. While anodal tDCS improved response latencies in large arithmetic problems, it decreased solution rates in small arithmetic problems. Likewise, the lower-alpha desynchronization in large problems increased, whereas the theta synchronization in small problems decreased. These findings reveal that the LPPC is differentially involved in solving small and large arithmetic problems and demonstrate that the effects of brain stimulation strikingly differ depending on the involved neuro-cognitive processes.

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Related in: MedlinePlus

Schematic depiction of a trial of the arithmetic task used in the present study.72 small (sums ≤ 10) and 72 large problems (sums > 10, with carry) were presented in a fixed pseudorandomized order.
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pone.0120665.g002: Schematic depiction of a trial of the arithmetic task used in the present study.72 small (sums ≤ 10) and 72 large problems (sums > 10, with carry) were presented in a fixed pseudorandomized order.

Mentions: Participants were instructed to solve the problems as accurately and fast as possible and to speak the answer into a microphone as soon as they had found the solution. A single trial (see Fig. 2) consisted of the presentation of a fixation point for 2000 ms, followed by the arithmetic problem that disappeared as soon as an oral response was registered. The problem was automatically faded out if no response was recorded within 10000 ms. Subsequently, an inter-trial interval with a length of 2500 ms was presented. E-Prime 2.0 software (Psychology Software Tools, Pittsburgh, PA) was used for stimulus delivery. Response latencies represented the time from problem onset to voice onset as registered by a voice key. Throughout the task, the experimenter recorded the correctness of each oral response and additionally noted rare problems arising with the collection of the vocal latencies (e.g. too late registration). The EEG cap was removed upon completion of the arithmetic task. At the end of the experiment, all participants were debriefed and received course credit.


When problem size matters: differential effects of brain stimulation on arithmetic problem solving and neural oscillations.

Rütsche B, Hauser TU, Jäncke L, Grabner RH - PLoS ONE (2015)

Schematic depiction of a trial of the arithmetic task used in the present study.72 small (sums ≤ 10) and 72 large problems (sums > 10, with carry) were presented in a fixed pseudorandomized order.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4366159&req=5

pone.0120665.g002: Schematic depiction of a trial of the arithmetic task used in the present study.72 small (sums ≤ 10) and 72 large problems (sums > 10, with carry) were presented in a fixed pseudorandomized order.
Mentions: Participants were instructed to solve the problems as accurately and fast as possible and to speak the answer into a microphone as soon as they had found the solution. A single trial (see Fig. 2) consisted of the presentation of a fixation point for 2000 ms, followed by the arithmetic problem that disappeared as soon as an oral response was registered. The problem was automatically faded out if no response was recorded within 10000 ms. Subsequently, an inter-trial interval with a length of 2500 ms was presented. E-Prime 2.0 software (Psychology Software Tools, Pittsburgh, PA) was used for stimulus delivery. Response latencies represented the time from problem onset to voice onset as registered by a voice key. Throughout the task, the experimenter recorded the correctness of each oral response and additionally noted rare problems arising with the collection of the vocal latencies (e.g. too late registration). The EEG cap was removed upon completion of the arithmetic task. At the end of the experiment, all participants were debriefed and received course credit.

Bottom Line: After the stimulation, we recorded their neural activity using EEG while the participants solved small and large arithmetic problems.Likewise, the lower-alpha desynchronization in large problems increased, whereas the theta synchronization in small problems decreased.These findings reveal that the LPPC is differentially involved in solving small and large arithmetic problems and demonstrate that the effects of brain stimulation strikingly differ depending on the involved neuro-cognitive processes.

View Article: PubMed Central - PubMed

Affiliation: Research on Learning and Instruction, Institute for Behavioral Sciences, ETH Zurich, Zurich, Switzerland; Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Zurich, Switzerland.

ABSTRACT
The problem size effect is a well-established finding in arithmetic problem solving and is characterized by worse performance in problems with larger compared to smaller operand size. Solving small and large arithmetic problems has also been shown to involve different cognitive processes and distinct electroencephalography (EEG) oscillations over the left posterior parietal cortex (LPPC). In this study, we aimed to provide further evidence for these dissociations by using transcranial direct current stimulation (tDCS). Participants underwent anodal (30min, 1.5 mA, LPPC) and sham tDCS. After the stimulation, we recorded their neural activity using EEG while the participants solved small and large arithmetic problems. We found that the tDCS effects on performance and oscillatory activity critically depended on the problem size. While anodal tDCS improved response latencies in large arithmetic problems, it decreased solution rates in small arithmetic problems. Likewise, the lower-alpha desynchronization in large problems increased, whereas the theta synchronization in small problems decreased. These findings reveal that the LPPC is differentially involved in solving small and large arithmetic problems and demonstrate that the effects of brain stimulation strikingly differ depending on the involved neuro-cognitive processes.

Show MeSH
Related in: MedlinePlus